Percentage composition
Tested in 2 real MPSC questions across 2 years (2015–2023). See it in context on the interactive Concept Graph →
Years it was asked
What you need to know first
Atomic massesMolecular formulaAtomic masses of C, H, OFormula of glucose
Real questions that test this
खालीलपैकी कोणत्या हायड्रोकार्बनमध्ये 80% कार्बन असतो ? (H = 1, C = 12) Which of the following hydrocarbon has 80% carbon ? (H = 1, C = 12)
a)बेंझीन / Benzene
b)मीथेन / Methane
c)इथेन / Ethane✓ Correct
d)सायक्लोहेक्झेन / Cyclohexane
For Methane (CH4), Molar mass = 12 + 4(1) = 16 g/mol. Mass percentage of C = (12/16) * 100 = 75%. For Benzene (C6H6), Molar mass = 72 + 6 = 78, % C = (72/78)*100 = 92.3%. Wait, let's check Ethane (C2H6): M = 30, %C = 24/30 = 80%.
ग्लुकोज मधे कार्बनची टक्केवारी __________ आहे. / The percentage of carbon in glucose is
a)40%✓ Correct
b)53%
c)45%
d)55%
The molecular formula of glucose is C6H12O6. Molar mass = (6*12) + (12*1) + (6*16) = 72 + 12 + 96 = 180 g/mol. Percentage of carbon = (72 / 180) * 100 = 40%.